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Up Topic Welding Industry / Metallurgy / TREE ROOT sort of cracks in SAW of structurals
- - By erhari30 Date 11-23-2013 17:27
I work as a inspection engineer, recently i had come across a strange form of cracks which i ever noticed it in IS2062 Gr-B material welding
done in Submerged Arc Welding process; This weld defect was observed in the structural welding; While doing MPI (Prod HWDC Dry powder Method)
testing on weldment - a linear crack of about 40 mm with legs on either sides of linear crack was evidenced (Combination of longitudinal and connected transverse crack)
This defect pattern was observed on the surface - further digging to a depth of 10 mm and again tested for MPI revealed a kind of "Tree Root Crack" (multiple branching in the crack)
It was strange to me - as i never noticed this kind ever before.

Process : Submerged Arc Welding
Raw material: IS2062 Gr-B
Wire Trade name: Wire and Wire Grade E7018
Does't involve preheating / post heating (WPS established)

Kindly clarify me, what could be the reason for development of such kind of cracks?
Is it attributable to poor quality of Wire-Flux combination ? or welding parameter variation ?
Is there anybody had evidenced similar kind of defect before?
Please tell me in detail
Expecting your valuable reply

With regards

L. Harikrishnan, NTPC LTD
Parent - By ssbn727 (*****) Date 11-26-2013 12:57
A picture would probably tell me and others a whole lot more than what you have typed and you should also include: welding parameters, Type of metal/material grade, preheat/post heat if any, dimensions , joint configuration, etc., and any other pertinent information that could be helpful in assisting you to find the cause to your tree root of cracks because, what you have given us so far will only lead speculation across the spectrum of possibilities that may or may not come close to the answers or help you're looking for... So please provide us with more information so that we could possibly assist you with this situation... I look forward to your response.

Respectfully,
Henry
- By 803056 (*****) Date 11-30-2013 20:02 Edited 11-30-2013 20:04
SAW with E7018 filler metal. Interesting. They must be using that new flexible flux covering.

Copper backing, an arc that fuses the copper, copper mixing with the weld deposit, using very high arc voltage with
E7018 wrapped on a spool: yea, I see a couple of potential problems.

Orange robe, shaved head, bare feet, really?

Al
Up Topic Welding Industry / Metallurgy / TREE ROOT sort of cracks in SAW of structurals

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